While the tin is falling, it is white-hot (12)
I believe the answer is:
incandescent
'white-hot' is the definition.
(synonyms)
'while the tin is falling it' is the wordplay.
I cannot quite understand how this works, but
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is located in the answer.
'tin' could be 'can' (synonyms) and 'can' is present in the answer.
'it' could be 'e' ('e' can mean 'electronic' which is similar to 'IT') and 'e' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
'is' acts as a link.
Can you help me to learn more?
(Other definitions for incandescent that I've seen before include "White-hot" , "Glowing with heat" , "Furious" , "livid" , "extremely angry" .)